Problem with rosdep install -i --from-path src --rosdistro foxy -y in tutorial

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Im fairly new to ROS and was trying to go through the ROS2 Tutorial. When Ive reached the "Writing a static broadcaster tutorial" and tried to check for missing dependencies with rosdep install -i --from-path src --rosdistro foxy -y , Ive received the following message:

ERROR: the following packages/stacks could not have their rosdep keys resolved to system dependencies: learning_tf2_py: Cannot locate rosdep definition for [tf2_ros_py]

Does anyone know how this problem can be fixed? (I am using Ubuntu 20.04 and foxy)

Ive already tried to delete the created package and to create a new one but this error keeps coming up nevertheless.